[ 764.6679369] panic: kernel diagnostic assertion "pmap->pm_obj[i].uo_npages == 0" failed: file "/syzkaller/managers/netbsd/kernel/sys/arch/x86/x86/pmap.c", line 2464 
[ 764.6679369] cpu0: Begin traceback...
[ 764.6781316] vpanic() at netbsd:vpanic+0x214
[ 764.6781316] _GLOBAL__sub_D_65535_0_cpu_configure() at netbsd:_GLOBAL__sub_D_65535_0_cpu_configure
[ 764.6884340] pmap_destroy() at netbsd:pmap_destroy+0x40d
[ 764.6979786] pmap_pp_remove() at netbsd:pmap_pp_remove+0x876
[ 764.7090116] uvm_anon_dispose() at netbsd:uvm_anon_dispose+0x179
[ 764.7182877] uvm_anon_freelst() at netbsd:uvm_anon_freelst+0x48
[ 764.7380284] amap_wipeout() at netbsd:amap_wipeout+0x237
[ 764.7480417] uvm_unmap_detach() at netbsd:uvm_unmap_detach+0x8b
[ 764.7580549] uvmspace_free() at netbsd:uvmspace_free+0x200
[ 764.7680679] exit1() at netbsd:exit1+0x39d
[ 764.7780803] sys_exit() at netbsd:sys_exit+0x6c
[ 764.7880965] syscall() at netbsd:syscall+0x32e
[ 764.7880965] --- syscall (number 1) ---
[ 764.8007071] 6ffcc24fe47a:
[ 764.8007071] cpu0: End traceback...

[ 764.8086206] dumping to dev 4,1 (offset=0, size=0): not possible
[ 764.8086206] rebooting...
SeaBIOS (version 1.8.2-20190122_225043-google)
Total RAM Size = 0x00000001e0000000 = 7680 MiB
CPUs found: 2     Max CPUs supported: 2
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f29c0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Booting from Hard Disk 0...

>> NetBSD/x86 BIOS Boot, Revision 5.10 (Tue Jul 17 14:59:51 UTC 2018) (from NetBSD 8.0)
>> Memory: 639/3144640 k

     1. Boot normally
     2. Boot single user
     3. Disable ACPI
     4. Disable ACPI and SMP
     5. Drop to boot prompt